package com.str.intro;
public interface MyString {

// Accessors
  public int length();
  // Return the length of this string.
		
  public char charAt(int i);
  // Return the character at index i in this string.
		
   public boolean equals(MyString that);
   // Return true if and only if this string is equal to that.
		
  public int compareTo(MyString that);
  // Return C1 if this string is lexicographically less than that, 
  // or 0 if this string is equal to that, 
  // or +1 if this string is lexicographically greater than that.
		
  public MyString substring(int i, int j);
  // Return the substring of this string consisting of the characters 
  // whose indices are i, , j1.
		
  public MyString concat(MyString that);
  // Return the string obtained by concatenating this string and 
  // that.
}
